Thread cutter for sewing machines



Ma s. 1928. 1,669,278

A G. W. BELL THREAD CUTTER FOR SEWING MACHINES Filed'Sept. 27, 1924 4 Sheets-Sheet 1 W 52 mm %ZLZZJM Guava/13 MIM May 8, 1928.

' G. W. BELL THREAD CUTTER FOR SEWING MACHINES Filed Sept. 27, 1924 4 Sheets-Sheet Ma s, 1928. 1,669,278

. G. W. BELL THREAD CUTTER FOR SEWING MACHINES Filed Sept. 2'7, 1924 4 eets-Sheet 5 7 '6" gff May 8, 192s. 1,669,278

G. w. BELL I THREAD CUTTER FOR SEWING MACHINES Filed Sept. 27, 1924 4 Sheets-Sheet 4 Patented May 8,1928. v

. UNITED:

P IENToI-"H E.

GEORGE WILLIAM ELL; oFNEw YORK, Ni Y., AssIeNoncro N'IoNsr Ec'IA QMncIIINn COMPANY, 01 CHICAGO; ILLI-NIs,1A CORPORATION on" ILLINOIS.

THREAD CU'IWIIEIRQ FOR SEWING' MACHINES. I

Application filed September 27,- 1924. Se rial No. 740,291.

The invention relates tonew and useful improvementsinthread cutters for sewing machines, andmore particularly to a thread cutter for a chain stitch sewing machine which operates to cutthe cnchained. loops between stitched articles. I 1

An object of the invention is located at the rear side of a fiatfwork sup port so that the enchained loops between a stitched article 7 and the. article being stitched may be directed into the thread cutter, by the weight of the stitched article passing off from the work support.

A further object of the invention is to provide a work support or extension thereofwhich is formed with a guiding slotfor directing the encha-ined thread loops into the thread cutting mechanism.

A still further object of the invention is to provide a machine of the above type. whereinthe thread cutter is operated contnr. uously duringthe running of the machine,

by a connection with the feed rocker which.

.operates the feed dog for moving the articles across the work support In the drawings which gitudinally of the work support and from the rear of the machine and showing the thread cutter in .rear elevation;

fFig. is a plan view of the parts beneath the work support, the standard being in section;

been applied is a flat bed machine, that is,

machine having a fiat work support. The bed plate is indicated at 1 and the flat work support is indicated at 2. The material is fed across the work support by means of a to providea thread cutter which is continuously operated when the machlne 1s runningand wh ch is showby way of illustration one embodiment of the inven-. 'tion I I Figure 1 is a View partly in section lon- Fig. 3 is a sectional view on the line 3 3 feed dog 3, which feed dog is carried by a feed bar .4 pivoted at 5 to a. feed rockerfi.

This feed rocker 6 is moved back and forth by means of an arm 7 which 15 connected to a link '8 which in turn is connected to a crank pin carried-on the end of the main shaft?) The feed bar is raised and lowered by an eccentric 10 mounted on themain shaft 9. ]These parts are of the usual con struction and further description thereof is not thought necessary. The feed rocker 6 is mounted at, its lower end on a short sup porting shaftll which is mounted in bears ings '12 and 13 at the rear side of the bed of the machine. The feed rocker is rigidly'secured to this shaft by means of set screws 14 and 15 (see Figures 5 and 6). The feed bar is secured to a pin 16 mounted in the upper end of the feed rocker 6.

The material is heldon the work support by means of a presser foot 1 7,and the material as itfis fed across the work support is stitchedby means ofa needle 18 and a coop.- erating looper 19 (see Figures Band 3).

This looperis ofv the; usual construction and forms a doublelocked chain stitch. 7 Such a stitching mechanism. will form aseri'esot enchained thread loops extending from one stitched article to another.

I The machine is E particularly adapted. for stitching materialto form bags. 'Theib ags are fed through underneath thepresser foot by means of the feed dog, one after another, and thebags are stitched up, anda connect: ed line ofenchained loops joins the stitched articles. i

so I

.The purpose; ofthc present invention is to provide a thread cutter for automatically severing the; enchained threads between stitched articles. This thread cutter includes a movable blade 20 and a stationary blade 21. Thestationary blade 21 is 1nounted on a bracket 22 scoured to the bed 2 of the machine at the rear side thereof, and pro: jects rearwardly to a point in rear of the feed rocker 6. This bracket 22 has an up-' wardly extending standard 23 which is formed with a slot 24 in which the stationary member 21' is located. A yoke bracket 25 is securedto this standard 23 and the movable member .20 is mounted in a swinging arm 26 which is rigidly connected to a fulcrum pin 27. This fulcrum pin is located in the yoke bracket 25. A spring 28 surrounding the fulcrum pin normally holds the cutting blades in shearing contact with each other. The swinging arm 26 is provided with a ball stud 29 with which a link 30 is connected.

The lower end of this link is in turn connected to a ball stud 31 carried at theouter end of an arm 32 attached to a sleeve 33 which is clamped by means of a screw 34 to the shaft 11 carrying the teed rocker. As the feed rocker moves back and forth, the arm 32" movable cutting blade to sever the thread laid between the cutting blades. Inasmuch as the arm projects rearwardly from the feed rocker, it is the upward movement of this arm which operates the movable cutting blade, and the upward movement of the arm 32 is caused by the forward movement of the feed rocker. In other words, the cutter is operated to severa thread when the feed bar is on its idle stroke.

This thread cutter is located directly in rear of the needle. The work support is provided with an extension 36 (see Figures 3 and 4), which is secured by screws 37 to the work support. This extension may be formed integral with the work support. The only thing essential is that the work support shall extend rearwardly so as to cover a thread cutting mechanism which is directlybeneath the same. Said extension 36 is provided with a slot 38, the side walls of "which are inclined at 39 away from each other toward the rear edge of the extension, and are curved. The purpose of thisslot with the curved walls is to direct the'thread connecting stitched articles into the. path of the cutting members. The cutting memhere are operated continuously during the running of the machine. A stitched article indicated at S in Fig. 3 passes over the extreme outer edge of the extension 36and by gravity is caused to swingunderneath said plate carrying the thread t which joins. this stitched article S to the article S being stitched into the path of the thread cutters.

From the above it will be apparent that I have provided what is known in the art as a flat bed' machine with means for automatically cutting the thread of enchained loops connecting stitched articles, and the thread iscuton the idlestroke of the feed bar, so that when the articles are fed forward by the active stroke of the feed bar, the cutters are open readyjtomreceive the enchained loops for cutting the same.

lNhile I have shown a connection to the feeding mechanism for operating the movablethread cutter, it will be understood that,

from the broad aspect oit'the inventiointhis thread cutter may be operated in any dosired way from the main shatt-of the machine, the essential feature being that the cutter be located at the rear of the flat work support and in the line, of feed sothat the article as it is fed out of the machine will cause the enchained stitch leading to said article to be moved into the thread cutter.

Having thus described the invention, what I claim as, new and desire to secure by Letters Patent, is

In a chain stitch sewing machine, a flat work support, stitching mechanism, a feed.

ing mechanism, a continuously operating thread cutter located at the rear side of the work support and in the line of feed, said feeding mechanism including a feed rocker located at the rear side of the work support, said thread cutter including-a stationary blade and a movable blade located in rear of the feed rocker and beneath the rear edge of the work support, said work support immediately above said thread cutter being slotted so as to permit the thread between stitched articlesto pass through the slot and into the range of the thread cutter, said feed rocker having a rearwardly projecting arm, said movable thread cutter having an arm. located above the arm on the feed rocker, and a link connecting the arm on the feed rocker to the arm of the movable blade so that the movable bladeis moved away from the stationary blade when the feeding mechanism operates to feed the material, thus separating the blades to permit the thread to enter therebetween.

In testimony whereof, I aflix my signature.

' GEORGE WILLIAM BELL. 

